1. Field of the Invention
The present invention is for a tub seal assembly for a clothes washing machine.
2. Description of the Related Art
The household and industrial clothes washing machine has an outer tub, an agitator, a perforated spin tub and a drive shaft which connects the motor and transmission to the agitator. The drive shaft extends axially through the bottom of the tub to the agitator and supports the perforated spin tub which is connected to the motor through the transmission. The spin tub is perforated along its sidewall so that water will be centrifugally forced from the spin tub when the spin tub is turned at a high rate of speed, or pumped from the spin tub when stationary.
To operate the washing machine, a user places clothes into the perforated spin tub. The outer tub is then partially filled with water. During a wash cycle, the agitator agitates, vibrates or oscillates the clothes to remove dirt and stains. After the rinse cycle is complete, the washing machine begins a spin cycle. Water is first pumped from the outer tub by a pump while the spinning tub removes excess water from the clothes.
During the washing and rinsing cycles when water is in the tub, a seal must be provided to prevent water from leaking into the electric drive motor and bearing assembly. However, seals of the existing art have encountered problems. One type of seal encountering such difficulty is a mechanical face seal, which typically consists of two faces, one face composed of a ceramic material and the other of a carbon-based material. Such mechanical face seals are subject to excessive wear from sand and dirt present in the washing fluid. Mechanical seal faces are held together by a spring to seal against tub wobble which results from unbalanced washing loads, and misalignment between the drive shaft, tub, bearing and seal. Such tub wobble and misalignment force open the seal faces resulting in leakage during routine operating conditions. Though shaft seals have typically been made from elastomeric compounds, such seals are not designed to maintain proper alignment of multiple parts within a washing machine.
The present invention is for a two-component seal for a spin tub of a washing machine. A bottom seal aligns and positions the tub while sealing against the tub bottom, the tub opening and the top seal. It aligns the top seal, the bearing and the drive shaft. The top and bottom tub seals are made of an elastomeric compound. The seals are reinforced with metal shapes to insure alignment of the drive shaft, bearing, tub and agitator. The resiliency of the seal material and the use of sealing lips also helps to accommodate any irregularity in the washing machine spin tub which may result in leaking.
The two-component seal is disposed about the tub opening and a metal shroud seal to prevent water in the washer from entering the motor and bearing space. The top seal includes a metal case with multiple sealing surfaces. The presence of multiple sealing surfaces prevent fluid, dirt and sand from destroying the sealing mechanism. Sealing lips stretch and a circumference spring provides a sealing force against the shaft shroud seal to seal during operation and to compensate for seal wear over time, extending the seal life. Multiple sealing surfaces are unitized to prevent fluid leakage and maintain the alignment of the drive shaft, bearing, tub and seal.
The top seal embodies a stiffener made of metal. A resilient elastomeric top cover encloses the stiffener, except for top and bottom tabs. The bottom tab prevents slipping between the tub seal and bottom assembly. The bottom tabs have lips which engage the shroud seal that are comprised of materials which allow the lips to seal on a softer metal shaft.
The bottom seal has a resilient metallic stiffener enclosed by a resilient bottom cover. The bottom seal has a vertical wall and a horizontal flange. Annular wedges on the bottom seal bias the bottom seal vertical wall inwardly, forming a resiliently expansible annular hub. The resilient biasing of the hub make the two-component seal self aligning as forces acting on the bearings to cause misalignment are counteracted and dampened by the reactive resilient biasing forces of the two-component seal.
It is therefore a principal object of the invention to seal water in the housing of a washing machine and prevent it from entering the motor and bearing space.
It is a further object of the invention to provide a two-component tub seal with redundant sealing mechanisms.
It is another object of the invention to provide a two-component tub seal which prevents misalignment of the bearing, drive shaft, tub and agitator assembly.
It is a still further object of the invention to provide a two-component tub seal which is durable and does not experience excessive wear.